Image forming apparatus

ABSTRACT

An image forming apparatus includes an image forming unit configured to form an image on a recoding medium, side plates extending on one end and another end of the image forming unit in a vertical direction thereof and configured to support the image forming unit, a main board including an element on a first board and fixed to the side plate on the one end such that the first board vertically extends on an outer side of the side plate, a sub-board including an element on a second board and electrically connected to the main board, a top surface member arranged above the image forming unit and including a sheet discharge tray, and a holding member configured to support the sub-board below the top surface member such that the second board extends in a direction intersecting with a plane on which the first board of the main board extends.

BACKGROUND Field of the Disclosure

The present disclosure relates to an image forming apparatus such as acopier and a printer that forms an image on a recording medium.

Description of the Related Art

In recent years, an image forming apparatus such as a laser beam printerhas been expected to be multifunctional to meet various user needs. Forexample, in communication with an information processing apparatus suchas a computer, wireless communication is demanded in addition to wiredconnection. In a conventional image forming apparatus that employs awireless communication technology, a configuration is used in which anexpansion board with a wireless communication antenna or a wirelesscommunication circuit is connected to a video controller board (aninterface board) having an external connection interface function(Japanese Patent Application Laid-Open No. 2006-56017).

SUMMARY OF THE DISCLOSURE

In recent years, an image forming apparatus such as a laser beam printerhas been expected to be smaller in size in addition to the demand for itto be multifunctional. If a video controller board and an expansionboard are arranged so as not to overlap and are connected via aconnecter cable as in the conventional configuration, an increase insize of space in which a board is to be arranged is unavoidable. Thishas hindered reduction in size of the image forming apparatus.

The present disclosure is directed to an image forming apparatus thatcan prevent an increase in size thereof even in a case where a sub-boardthat expands or complements a function of a main board is connected tothe main board.

According to an aspect of the present disclosure, an image formingapparatus includes an image forming unit configured to form an image ona recoding medium, side plates arranged on one end and another end ofthe image forming unit to extend in a vertical direction thereof andconfigured to support the image forming unit, a main board that is anelectronic circuit board including an element on a first board and isfixed to the side plate on the one end such that the first board extendsin the vertical direction on an outer side of the side plate, asub-board that is an electronic circuit board including an element on asecond board and is electrically connected to the main board, a topsurface member arranged above the image forming unit and including asheet discharge tray on which a recording medium with an image formed bythe image forming unit is to be discharged, and a holding memberconfigured to support the sub-board below the top surface member suchthat the second board extends in a direction intersecting with a planeon which the first board of the main board extends.

Further features of the present disclosure will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view illustrating an image formingapparatus according to a first exemplary embodiment.

FIG. 2 is a perspective view illustrating a configuration of the imageforming apparatus according to the first exemplary embodiment.

FIG. 3 is a perspective view illustrating a holding member in the imageforming apparatus according to the first exemplary embodiment.

FIG. 4 is a schematic sectional view illustrating the holding memberaccording to the first exemplary embodiment.

FIG. 5 is a perspective view illustrating a holding member to be used inan image forming apparatus according to a modification example.

FIG. 6 is a perspective view illustrating the holding member in theimage forming apparatus according to the modification example.

DESCRIPTION OF THE EMBODIMENTS

A first exemplary embodiment will be described. An image formingapparatus 1 according to the first exemplary embodiment is anelectrophotographic laser beam printer that performs recording byemitting a laser beam to a photosensitive member.

FIG. 1 is a sectional view of a main mechanical unit of the imageforming apparatus 1 according to the first exemplary embodiment.

(Overall Configuration of Image Forming Apparatus)

In FIG. 1, the image forming apparatus 1 includes a sheet feedingcassette 2 as a recording medium storage unit in which recording sheetsP as recording media to be fed to the image forming apparatus 1 arestored. A sheet feeding roller 8 a as a sheet feeding portion isarranged in an upper front end of the sheet feeding cassette 2 in anapparatus body, and a pressurizing plate 2 a as a pressing member isarranged under the stacked recording sheets P. The recording sheets Pstored in the sheet feeding cassette 2 are pressed by the sheet feedingroller 8 a and the pressurizing plate 2 a, and are then picked up. Therecording sheets P stacked in the sheet feeding cassette 2 are separatedone by one by a sheet feeding roller 8 b and a separation mechanism 8 c,and each separated recording sheet P is fed to a registration rollerpair 9. The registration roller pair 9 is arranged in a conveyance pathto convey the recording sheet P fed by the sheet feeding roller 8 b toan image forming unit.

The image forming unit includes a plurality of process cartridges 7, alaser scanner (a light irradiation unit) 6, an intermediate transferunit 4, and a secondary transfer roller 10. In the present exemplaryembodiment, the plurality of process cartridges 7 is arranged forrespective four colors of yellow, magenta, cyan and black. The pluralityof process cartridges 7 only differs from each other in color of toner(developer) stored therein but has the same configuration. Each of theplurality of process cartridges 7 includes a developing device, acleaner, a charging roller, toner that are not illustrated, and aphotosensitive drum 7 a. The intermediate transfer unit 4 includes thesecondary transfer roller 10, an intermediate transfer belt 4 a as anendless belt that rotationally moves, a counter roller 4 b, a drivenroller 4 c, and a drive roller 4 d. The counter roller 4 b, the drivenroller 4 c, and the drive roller 4 d are arranged on an inner peripheralsurface of the intermediate transfer belt 4 a. The intermediate transferbelt 4 a is stretched by the counter roller 4 b and the driven roller 4c, and the drive roller 4 d applies certain tension to the intermediatetransfer belt 4 a so as to transmit a driving force. A plurality ofprimary transfer rollers 4 e is arranged opposite the respectivephotosensitive drums 7 a via the intermediate transfer belt 4 a. Thesecondary transfer roller 10 is arranged opposite the counter roller 4 bvia the intermediate transfer belt 4 a.

In each of the process cartridges 7, the charging roller charges asurface of the photosensitive drum 7 a, and the laser scanner 6 emits alaser beam corresponding to image information to the photosensitive drum7 a to form a latent image. Then, in each of the process cartridges 7,the developing device develops the latent image, thereby forming a tonerimage on the surface of the photosensitive drum 7 a. In such a manner,toner images of yellow, magenta, cyan, and black are formed on thephotosensitive drums 7 a in the respective process cartridges 7. Whenvoltages are applied to the primary transfer rollers 4 e, the tonerimages are sequentially transferred to the intermediate transfer belt 4a in respective primary transfer portions between the photosensitivedrums 7 a and the primary transfer rollers 4 e. Then, each of the tonerimages is superimposed on the intermediate transfer belt 4 a, therebyforming a color toner image on the intermediate transfer belt 4 a. Thecolor toner image transferred to the intermediate transfer belt 4 a issecondarily transferred to a recording sheet P supplied by theregistration roller pair 9 at a timing when the color toner image entersa nip portion between the secondary transfer roller 10 and the counterroller 4 b. The toner image transferred to the recording sheet P in theimage forming unit is conveyed to a fixing device 5. In the fixingdevice 5, the toner image is fixed on the conveyed recording sheet Pwith heat. Then, a discharge roller pair 11 discharges the recordingsheet P with the toner image fixed thereon to a sheet discharge tray 12arranged on an upper surface of the image forming apparatus 1.

(Frame Configuration of Image Forming Apparatus)

A basic structure of the image forming apparatus 1 includes side plates14 a and a plurality of stays 14 b as connecting members as illustratedin FIG. 2. As illustrated in FIG. 2, the side plates 14 a are extendingin a vertical direction and arranged on both sides of the image formingunit configured to form an image on a recording sheet P. Each of thestays 14 b is arranged in a horizontal direction between the side plates14 a to connect the side plates 14 a. The side plates 14 a are arrangedopposite each other with the sheet feeding cassette 2, the processcartridge 7, the fixing device 5, and the sheet discharge tray 12therebetween. The side plates 14 a and the plurality of stays 14 b aremembers formed of plate-shaped members made of metal. A structure formedby the side plates 14 a and the stays 14 b functions as a frame 14 ofthe image forming apparatus 1, and members inside the image formingapparatus 1 are supported by the frame 14. An exterior member 13(FIG. 1) made of resin is fixed to the frame 14, so that the imageforming apparatus 1 is formed.

The exterior member 13 includes a top surface member 13 a, a sidesurface member 13 b (FIG. 1), a front surface member 13 c, and a backsurface member 13 d. The top surface member 13 a includes the sheetdischarge tray 12 having a recess shape, and is arranged verticallyabove the image forming unit. The side surface members 13 b are fixed tothe side plates 14 a arranged on the both sides of the frame 14. Each ofthe side surface members 13 b is arranged on an outer side of the sideplate 14 a relative to the apparatus. The front surface member 13 c isarranged on an apparatus front surface, and a portion thereof is openedand closed. The back surface member 13 d is arranged on an apparatusback surface.

(Arrangement of Interface Board)

The image forming apparatus 1 includes various electronic circuit boardshaving elements arranged on boards. Since the electronic circuit boardcannot be arranged in a position in which the electronic circuit boardinterferes with components such as the sheet feeding cassette 2, theprocess cartridges 7, and the fixing device 5 arranged between the sideplates 14 a, the electronic circuit board is arranged such that theboard extends in the vertical direction between the side plate 14 a andthe side surface member 13 b. For example, as illustrated in FIG. 2, theimage forming apparatus 1 includes an interface board 20 (a main board)to which information is input from an external information device suchas a host computer. The interface board 20 includes a basic input-outputterminal such as a universal serial bus (USB) port and a local areanetwork (LAN) port. Since the input-output terminal is arranged on theapparatus back surface, the interface board 20 needs to be arranged onthe apparatus back surface. Accordingly, a location where the interfaceboard 20 can be arranged is limited in the image forming apparatus 1.

Meanwhile, an extension board 22 (a sub-board) can be connected to theinterface board 20 so that the interface board 20 can accommodate otherfunctions in addition to a function of the interface board 20 itself.The term “other functions” used herein includes a communication functioncompliant with a communication method such as a wireless fidelity(Wi-Fi) method and a near field communication (NFC) method, and a backupfunction of storing an operation state of the apparatus body even in acase where the interface board 20 is replaced. Consequently, in a casewhere the extension board 22 for extending a function is to beconnected, a space in which the extension board 22 is to be arrangedbecomes necessary in addition to a space for the interface board 20.This hinders reduction in size of the image forming apparatus.

In the present exemplary embodiment, as illustrated in FIGS. 3 and 4, aholding member 23 is used to support the extension board 22 such that aboard (a second board) of the extension board 22 extends in a directionintersecting with a board (a first board) of the interface board 20. Inother words, the extension board 22 is arranged such that the board ofthe extension board 22 extends in the horizontal direction verticallybelow the top surface member 13 a, more specifically, vertically belowthe sheet discharge tray 12.

The holding member 23 is fixed via a resin-made supporting member 15fixed to the side plate 14 a. The supporting member 15 includes aprotruding portion 15 a and an engaging portion (not illustrated) havinga through hole. The protruding portion 15 a protrudes outward in avertical manner from the side plate 14 a so as to be away from the sideplate 14 a. The holding member 23 includes an opening portion 23 a and asnap-fit portion 23 e. The protruding portion 15 a of the supportingmember 15 is inserted into the opening portion 23 a of the holdingmember 23 and, at the same time, the snap-fit portion of the holdingmember 23 is engaged with the engaging portion of the supporting member15, so that the holding member 23 is fixed to the supporting member 15.In this manner, the holding member 23 can be simply fixed by beinginserted into the supporting member 15 toward a direction perpendicularto the side plate 14 a.

The extension board 22 is rotated about one end of a board surface, sothat the extension board 22 is fixed to the holding member 23. Theholding member 23 includes a supporting surface 23 b that supports theextension board 22. Moreover, the holding member 23 includes aregulation portion 23 c and a snap-fit portion 23 e that respectivelycorrespond to one side and the other side of opposite sides of theextension board 22. The regulation portion 23 c causes the extensionboard 22 to be positioned between the supporting surface 23 b and theregulation portion 23 c to prevent an upward movement of the extensionboard 22. More particularly, the regulation portion 23 c is a portionthat is formed to protrude through a portion of the extension board 22from a wall surface 23 d facing one of the sides of the extension board22. Accordingly, one end of the extension board 22 contacts the wallsurface 23 d between the regulation portion 23 c and the supportingsurface 23 b, and the extension board 22 is rotated about such a contactportion. Thus, the extension board 22 contacts, distorts and pushes thesnap-fit portion 23 e, and then is inserted into the holding member 23.As a result, an upward movement of the extension board 22 inserted intothe holding member 23 is regulated at one end by the regulation portion23 c and the other end by the snap-fit portion 23 e while the extensionboard 22 is being supported by the supporting surface 23 b. Moreover, ina direction in which the board surface of the extension board 22extends, a movement of the extension board 22 inserted into the holdingmember 23 toward a direction in which the regulation portion 23 c andthe snap-fit portion 23 e are opposite is regulated. In the presentexemplary embodiment, in addition to the wall surface 23 d and thesnap-fit portion 23 e which are arranged so as to be opposite tocorrespond to the opposite sides of the extension board 22, wallsurfaces are arranged so as to correspond to the other opposite sides ofthe extension board 22. Accordingly, in a direction in which the boardsurface of the extension board 22 extends, a movement of the extensionboard 22 inserted into the holding member 23 toward a directionintersecting with the direction in which the regulation portion 23 c andthe snap-fit portion 23 e are opposite is regulated.

(Connection of Interface Board to Expansion Board)

The extension board 22 and the interface board 20 are electricallyconnected via a connector wiring 24. The connector wiring 24 has aconfiguration in which male connectors are attached to both ends ofwiring. The male connector at one end of the connector wiring 24 isconnected to a female connector of the extension board 22, whereas themale connector at the other end of the connector wiring 24 is connectedto a female connector of the interface board 20. Thus, two boards, theextension board 22 and the interface board 20, are connected to theconnector wiring 24. In the present exemplary embodiment, the wiring ofthe connector wiring 24 passes a predetermined position by a guideportion 15 b of the supporting member 15.

(Description of Effect)

The configuration as described above can prevent an increase in size ofthe image forming apparatus 1 in comparison with a case in which a boardsurface of the extension board 22 and a board surface of the interfaceboard 20 are arranged on a same plane. In a case where the extensionboard 22 is arranged on the side plate 14 a, a space for the extensionboard 22 is difficult to obtain due to the interface board 20 and apower source board 16 arranged thereon. Even in a case where theextension board 22 is arranged thereon, the degree of structuralflexibility is low. However, in the present exemplary embodiment, theextension board 22 is arranged so as to intersect with the interfaceboard 20, thereby enhancing the degree of structural flexibility.Accordingly, in a case where a backup member including a battery and astorage element that stores an operation state of the apparatus is to bearranged with the extension board 22, the connector wiring 24 can bearranged in a position where the connector wiring 24 is not necessarilyextended. Meanwhile, in a case where a communication board that allowsfor a communication method such as a Wi-Fi method and an NFC method isto be arranged with the extension board 22, a wireless communicationantenna portion included in the communication board is arrangedvertically below the sheet discharge tray 12. Hence, electric waves tobe transmitted and received can be prevented from being blocked by theside plates 14 a made of metal. Alternatively, the wirelesscommunication antenna portion included in the communication board may bearranged away from a motor (not illustrated) as a drive source or thepower source board 16 that can be a noise source, so that good receptioncan be obtained.

The protruding portion 15 a of the supporting member 15 is inserted intothe opening portion 23 a of the holding member 23 in a state in whichthe holding member 23 is holding the extension board 22. At the sametime, a snap-fit portion (not illustrated) of the holding member 23 isengaged with an engaging portion of the supporting member 15. Thus, theholding member 23 is fixed to the supporting member 15. In such amanner, the holding member 23 is inserted into the supporting member 15in a direction perpendicular to the side plate 14 a, so that the holdingmember 23 can be simply fixed. Moreover, the insertion of the holdingmember 23 into the supporting member 15 in the direction perpendicularto the side plate 14 a allows the holding member 23 to be detachable.Thus, by removing the side surface member 13 b fixed to the side plate14 a, the extension board 22 held by the holding member 23 can bedetached, for example, without removal of the top surface member 13 a.

MODIFICATION EXAMPLE

In the first exemplary embodiment, the supporting member 15 and theholding member 23 respectively include the protruding portion 15 a andthe opening portion 23 a, and the opening portion 23 a of the holdingmember 23 is guided by the protruding portion 15 a of the supportingmember 15 such that the holding member 23 is inserted in a certaindirection. However, the holding member 23 can be directly fixed to theside plate 14 a without the supporting member 15. The supporting member15 and the holding member 23 may not respectively include the protrudingportion 15 a and the opening portion 23 a.

In a modification example of the exemplary embodiment, as illustrated inFIGS. 5 and 6, a bending surface 14 a 1 is formed on a side plate 14 ato be bent and protrude outward, and a groove portion 23 f is formed ina holding member 23 to nip and hold the bending surface 14 a 1 so that avertical movement of the holding member 23 is regulated thereby.Moreover, the holding member 23 includes two snap-fit portions 25 inpositions facing each other. The two snap-fit portions 25 includerespective claw portions 26 on surfaces facing each other. The clawportions 26 includes a guiding surface and a step portion respectively.The two snap-fit portions 25 hold the side plate 14 a therebetween sothat a movement of the apparatus in a front-back direction is regulated,and at the same time the holding member 23 is prevented from beingdisplaced from the side plate 14 a by the claw portions 26.Particularly, in the present modification example, the snap-fit portion25 is displaced to be separated from an engaging portion of the sideplate 14 a by applying a force on an opposite end of the end on whichthe claw portion 26 of the snap-fit portion 25 is formed, therebyreleasing the claw portion 26 and the side plate 14 a.

In the present modification example, not only an effect similar to thefirst exemplary embodiment can be obtained, but also the holding member23 holding the extension board 22 can be readily removed. Moreover,various changes can be made within the scope of the present disclosure.For example, the configuration in which the bending surface 14 a 1 ofthe side plate 14 a is nipped and held by the groove portion 23 f of theholding member 23 according to the present modification example is addedto the configuration of the first exemplary embodiment.

While the present disclosure has been described with reference toexemplary embodiments, it is to be understood that the disclosure is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2019-068047, filed Mar. 29, 2019, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. An image forming apparatus comprising: an imageforming unit configured to form an image on a recoding medium; sideplates arranged on one end and another end of the image forming unit toextend in a vertical direction thereof and configured to support theimage forming unit; a main board that is an electronic circuit boardincluding an element on a first board and is fixed to the side plate onthe one end such that the first board extends in the vertical directionon an outer side of the side plate; a sub-board that is an electroniccircuit board including an element on a second board and is electricallyconnected to the main board; a top surface member arranged above theimage forming unit and including a sheet discharge tray onto which arecording medium with an image formed by the image forming unit is to bedischarged; and a holding member configured to support the sub-boardbelow the top surface member such that the second board extends in adirection intersecting with a plane on which the first board of the mainboard extends.
 2. The image forming apparatus according to claim 1,wherein the side plate is made of metal, wherein the image formingapparatus further comprises a supporting member that is made of resinand attached to the side plate, and wherein the holding member is fixedto the side plate via the supporting member.
 3. The image formingapparatus according to claim 2, wherein the supporting member includes aprotruding portion that protrudes in a direction extending from the sideplate on the one end, wherein the holding member includes an openingportion, and wherein the holding member is positioned such that theopening portion is engaged with the protruding portion.
 4. The imageforming apparatus according to claim 1, wherein the holding memberincludes a snap-fit portion, and the holding member is fixed to the sideplate by the snap-fit portion.
 5. The image forming apparatus accordingto claim 1, wherein the holding member includes a supporting surfacethat supports the sub-board, a wall surface including a regulationportion that regulates the sub-board to move vertically upward, and asecond snap-fit portion that is arranged facing the wall surface andsandwiches the sub-board with the wall surface.
 6. The image formingapparatus according to claim 5, further comprising a side surface memberconfigured to cover the main board so as to sandwich the main board withthe side plate, wherein the sub-board attached to the holding member isdetachable by removing the side surface member from the image formingapparatus
 7. The image forming apparatus according to claim 1, whereinthe main board is an interface board to which information can be inputfrom an external information device.
 8. The image forming apparatusaccording to claim 7, wherein the sub-board is a communication board. 9.The image forming apparatus according to claim 7, wherein the sub-boardis a backup member including a storage element and a battery.